Novel photographic color coupling compounds

ABSTRACT

Novel magenta-forming 3-anilino-2-pyrazolin-5-one color couplers for use in silver halide photography are described wherein the anilino group carries an aryloxysulphonyl group.

This is a division of application Ser. No. 452,325 filed Mar. 18, 1974now U.S. Pat. No. 3,930,861.

The present invention relates to 2-pyrazolin-5-one colour couplers, tothe preparation thereof, to photographic silver halide elements anddeveloping compositions containing such colour couplers as well as tocolour development processes wherein said colour couplers take part inthe formation of a magenta dye image.

It is known that for the formation of a photographic colour image in alight-sensitive silver halide emulsion layer the exposed silver halideis developed by means of an aromatic primary amino colour developer inthe presence of a colour coupler which by reaction with the oxidizeddeveloper forms a dye on the areas corresponding to the silver image.

In subtractive three-colour photography it is common practice to use aphotographic element comprising at least one red-sensitized,green-sensitized and blue-sensitive silver halide emulsion layer,wherein upon development in the presence of suitable colour couplers,cyan, magenta and yellow dye images are formed respectively.

It is desirable that colour couplers employed in colour photography havegood coupling activity, and produce dye images that have the desiredspectral absorption characteristics and favourable stability againstlight, moisture and heat.

The colour couplers may be of the diffusible type or of thenon-diffusible type. By diffusible couplers is meant colour couplers thedispersability or solubility of which is sufficient to enable them to beusefully incorporated in aqueous colour developing solutions whereas bynon-diffusible colour couplers is meant colour couplers intended for usein the photographic element where they should remain during colourdevelopment. Non-diffusible colour couplers are usually obtained byproviding in the colour coupler molecule one or more ballasting groupswhich are sufficiently large to prevent diffusion of the colour couplere.g. aliphatic groups of 5 to 20 C-atoms.

It is known that for homogeneously distributing nondiffusible colourcouplers in a hydrophilic colloid layer, more particularly a silverhalide emulsion layer, special techniques are to be used. Colourcouplers containing a water-solubilizing group e.g. a sulpho group canbe incorporated in the hydrophilic colloid compositions from alkalinesolutions if necessary in the presence of a water-miscible solvent e.g.ethanol. Water-insoluble or sparingly water-soluble colour couplers canbe incorporated in hydrophilic colloid compositions by dispersingtechniques using highboiling water-immiscible solvents e.g. tricresylphosphate and dibutylphthalate and/or low boiling water-immisciblesolvents e.g. methylene chloride, ethyl acetate, diethyl carbonate, etc.No matter what technique is used, the colour couplers should behomogeneously distributed in the hydrophilic colloid layer and have highstability against crystallization so that colour image formation is notimpaired.

For the formation of the magenta separation image it is known to use2-pyrazolin-5-one colour couplers. These colour couplers may comprise inthe 1-position an alkyl or substituted alkyl group e.g. alkyl with 1 to22 C-atoms, haloalkyl e.g. chloro and fluoroalkyl, cyanoalkyl, e.g.β-cyanoethyl, benzyl, etc., an aryl or substituted aryl group e.g.phenyl, 2-chlorophenyl, 2,6-dichlorophenyl, 2,4,6-trichlorophenyl,2,4-dichloro-6-methylphenyl, 2-chloro-4,6-dimethylphenyl, cyanophenyl,alkoxyphenyl, alkylthiophenyl, alkylsulphonylphenyl, sulphamoyl- orcarbamoylphenyl etc. or a heterocycle e.g. 2-thiazolyl,2-benzothiazolyl, 2-imidazolyl, 2-benzimidazolyl, 2-oxazolyl,2-benzoxazolyl, etc.

In the 3-position of 2-pyrazolin-5-one colour couplers, there is usuallyan alkylamino group, an arylamino group, an acylamino group, anacyloxyamino group or an ureido group.

In accordance with the present invention novel 2-pyrazolin-5-one colourcouplers comprising in the 3-position an anilino group are providedwhich yield upon colour development azomethine dyes having favourablesensitometric and spectral properties with high transmission for blueand red light and favourable stability against light, heat and moisture.Moreover, the non-diffusible types of these colour couplers lendthemselves very well for being incorporated in hydrophilic colloidcompositions more particularly a light-sensitive silver halide emulsionby means of dispersion techniques and stable, finely divided dispersionsof the colour couplers in the emulsion layers can be obtained in thisway.

The 3-anilino-2-pyrazolin-5-one colour couplers according to the presentinvention are characterized in that the anilino group carries anaryloxysulphonyl group including a substituted aryloxysulphonyl group.The aryloxysulphonyl group has a high stability against hydrolysiscontrary to alkoxysulphonyl groups which as is known from British Pat.No. 843,940 are hydrolytically unstable.

More particularly, the 3-anilino-2-pyrazolin-5-one colour couplersaccording to the present invention can be represented by the formula:##STR1## wherein: R₁ represents alkyl including substituted alkyl e.g.benzyl, substituted benzyl e.g. chlorobenzyl, cyanoalkyl, e.g.2-cyanoethyl, fluoroalkyl e.g. 2,2,2-trifluoroethyl, aryl includingsubstituted aryl e.g. aryl substituted with one or more alkyl, alkoxy,alkylthio, phenoxy, halogen, alkylsulphonyl, carbalkoxy,fluorosulphonyl, trifluoromethyl, sulphamoyl, carbamoyl, cyano or nitrogroups, or a heterocycle,

X represents hydrogen or a substituent that exhibits two-equivalentcharacter on colour development e.g. a halogen atom e.g. chlorine atom,an alkylthio, arylthio, or heterocyclic thio group, an alkoxy, aryloxyor acyloxy group, a sulpho group or an arylazo group,

Ar represents a phenyl group or substituted phenyl group carrying anaryloxysulphonyl group e.g. a phenyloxysulphonyl group which may besubstituted e.g. with one or more alkyl, cycloalkyl, hydroxy, halogen,alkoxy, allkylthio or alkylsulphonyl groups; more particularly Arrepresents a group of the formule: ##STR2## wherein: Z is hydrogen,halogen, alkoxy, alkylthio, etc., and

A is a carbocyclic aryl group e.g. phenyl which may be substituted e.g.with one or more of the groups alkyl, cycloalkyl, hydroxy, halogen,alkoxy, alkylthio or alkylsulphonyl.

The term "two-equivalent character" as applied to colour couplingsystems is well known and is described for example in "The theory of thephotographic process", C. E. K. Mees, The Mac Millan Company, New York,1966, p.390. It means that by the presence of the splittable substituenton the active methylene group only two equivalents of silver arerequired for the formation of the dye contrary to four equivalents whenthe methylene group is not substituted.

The colour couplers for magenta according to the present invention canbe of the diffusible- or non-diffusible type as described above. Theinvention is particularly concerned with non-diffusible colour couplersfor use in the photographic colour element itself. For this purpose thecolour couplers can be provided in the substituents on the 1- or3-positions of the pyrazolon nucleus with one or more ballasting groupscomprising an aliphatic straight-chain or branched-chain hydrocarbongroup of at least 5 C-atoms. The ballasting group(s) rendering thecolour coupler fast to diffusion in hydrophilic colloid layers ispreferably a substituent on the aryloxysulphonyl group or a substituenton a 1-aryl group. These non-diffusible colour couplers of the inventionlend themselves very well for being incorporated in the silver halideemulsion by dispersing techniques.

The present invention provides besides novel 2-pyrazolin5-one compounds,a method of producing a magenta coloured photographic image in aphotographic light-sensitive silver halide material which comprisesexposing the material and developing it with an aromatic primary aminocolour developing agent in the presence of a 2-pyrazolin-5-one colourcoupler as defined above.

The present invention further provides a photographic element containingat least one silver halide emulsion layer and a 2-pyrazolin-5-one colourcoupler as defined above comprising in its molecule one or morealiphatic hydrocarbon groups of at least 5 C-atoms.

The colour couplers of the present invention can be prepared accordingto methods known in the art. For example, they can be prepared byreaction of the known alkyl or aryl hydrazines with anaryloxysulphonylaniline and ethyl β,β,β-trimethoxypropionate accordingto the method described in the published German Patent Application No.2,042,920.

The aryloxysulphonylanilines can be prepared by means of one of thefollowing procedures:

(1) reaction of a nitrobenzene sulphochloride with a phenol or naphtholin pyridine followed by catalytic hydrogenation;

(2) reaction of an acetylaminobenzene sulphochloride with a phenol ornaphthol in pyridine followed by deacetylation, and

(3) reaction of a nitrobenzene sulphochloride with the sodium salt of aphenol or naphthol in benzene followed by catalytic hydrogenation.

Representative aryloxysulphonylanilines prepared according to one of theabove procedures and useful for the preparation of the colour couplersof the invention are listed in the following Table I.

                  Table I                                                         ______________________________________                                                                         Melt-                                                                  Pro-   ing                                                                    ce-    point                                        Amine compound            dure   ° C                                   ______________________________________                                         ##STR3##                 1      106                                           ##STR4##                 1      119                                           ##STR5##                 1      165                                           ##STR6##                 2      103                                           ##STR7##                 2      98                                            ##STR8##                 1      146                                           ##STR9##                 3      105                                           ##STR10##                3      101                                           ##STR11##                1      73                                            ##STR12##                1      113                                           ##STR13##                1      146                                           ##STR14##                1      138                                           ##STR15##                2      63                                            ##STR16##                2      135                                          ______________________________________                                    

The following preparations illustrate how the colour couplers of theinvention can be prepared. Representative examples of colour couplersare listed in table II hereinafter.

PREPARATION 1: COLOUR COUPLER 1 OF TABLE II

38.9 g. (0.1 mole) of amine(1) in 100 ml of acetic acid were stirred for90 min. at room temperature with 28.8 g (0.12 mole) of ethylβ,β,β-trimethoxypropionate (for 80% pure). The excess of acetic acid andpropionate was removed by evaporation at 100°-110° C under reducedpressure of 1 mm Hg. 11.4 g (0.1 mole) of 2,2,2-trifluoroethylhydrazine(prepared according to the British Pat. No. 1,069,532 and 1 ml of aceticacid were added to the residue. Stirring was continued for 15 min. at100°-110° C and the reaction mixture became solid. It was recrystallizedfrom 200 ml of ethanol.

Yield: 34.6 g (62.5%). Melting point: 201° C.

PREPARATION 2: COLOUR COUPLER 2 OF TABLE II

37.3 g (0.1 mole) of amine (2) in 100 ml of acetic acid were allowed toreact as described in preparation 1 with 0.12 mole of ethylβ,β,β-trimethoxypropionate.

After evaporation, 12.2 g (0.1 mole) of benzylhydrazine and 1 ml ofacetic acid were added. The mixture was stirred for 21/2 hours at100°-110° C and then concentrated by evaporation. The residue wasrecrystallized from 160 ml of methanol.

Yield: 23.5 g (43%). Melting point: 193° C.

PREPARATION 3: COLOUR COUPLER 8 OF TABLE II

This coupler was prepared from 39.1 g (0.1 mole) of amine (5), 100 ml ofacetic acid, 0.12 mole of ethyl β,β,β-trimethoxypropionate and 11.4 g(0.1 mole) of 2,2,2-trifluoroethylhydrazine according to the procedureof preparation 2. The recrystallization solvent was isopropylether.

Yield: 34 g (61.2%). Melting point: 167° C.

PREPARATION 4: COLOUR COUPLER 9 OF TABLE II

This coupler was prepared from 32.1 g (0.1 mole) of amine (3), 100 ml ofacetic acid, 0.12 mole of ethyl β,β,β-trimethoxypropionate and 19 g (0.1mole) of α-trifluoromethyl benzylhydrazine (prepared as described inBritish Patent 1,069,532) following the procedure of preparation 2. Therecrystallization solvent was benzene.

Yield: 38 g (67.5%). Melting point: 149° C.

PREPARATION 5: COLOUR COUPLER 10 OF TABLE II

This coupler was prepared from 39.55 g (0.1 mole) of amine (7), 100 mlof acetic acid, 0.12 mole of ethyl β,β,β-trimethoxypropionate, and 11.4g (0.1 mole) of 2,2,2-trifluoroethylhydrazine following the procedure ofpreparation 2. The recrystallization solvent was isopropyl ether.

Yield: 27 g (48.5%). Melting point: 139°-141° C.

PREPARATION 6: COLOUR COUPLER 13 OF TABLE II

This coupler was prepared from 45.9 g (0.1 mole) of amine (9), 100 ml ofacetic acid, 0.12 mole of ethyl β,β,β-trimethoxypropionate, and 13.4 g(0.11 mole) of benzylhydrazine. The residue was recrystallized frommethanol and then from ethanol.

Yield: 19 g (30%). Melting point: 89° C.

PREPARATION 7: COLOUR COUPLER 18 OF TABLE II

24.9 g (0.1 mole) of amine (6), 28.8 g (0.12 mole) of ethylβ,β,β-trimethoxypropionate and 2 ml of acetic acid were heated for 3hours at 80° C. The excess of acetic acid and propionate was removed byevaporation at 100°-110° C under reduced pressure of 1 mm Hg.

39.6 g (0.1 mole) of p-n-hexadecylsulphonylphenylhydrazine, 150 ml ofacetonitrile, and 2ml of acetic acid were added to the residue. Themixture was heated until complete dissolution and then left standing atroom-temperature. The precipitate formed was filtered off by suction andrecrystallized, first from isopropyl ether and then from acetonitrile.

Yield: 20.5 g (30%). Melting point: 74° C.

PREPARATION 8: COLOUR COUPLER 21 OF TABLE II

38.9 g (0.1 mole) of amine (1) and 0.12 mole of ethyl β,β,β-trimethoxypropionate were allowed to react in acetic acid as described inpreparation 1.

After evaporation, 0.1 mole of 2,4-dimethyl-6-chlorophenyl hydrazine and10 ml of acetic acid were added to the residue. The reaction mixture wasstirred at 80° C for 1 hour and then suddenly became solid. It wastreated with hot acetonitrile.

Yield: 36.6 g (60%). Melting point: 226° C.

PREPARATION 9: COLOUR COUPLER 25 OF TABLE II

This coupler was prepared from 40.3 g (0.1 mole) of amine (4), 0.12 moleof ethyl β,β,β-trimethoxypropionate, 2 ml of acetic acid and 21.15 g(0.1 mole) of 2,4,5-trichlorophenyl hydrazine following the procedure ofpreparation 7.

However, the reaction mixture was left standing overnight andcyclisation was effected by addition of 50 ml of 0.2 N sodium methylatein methanol and heating for 2 hours at 50° C. After acidification withacetic acid and dilution with water, the mixture was extracted withmethylene chloride. The residue obtained upon evaporation was treatedwith methanol.

Yield: 34 g (51%). Melting point: 136° C.

PREPARATION 10: COLOUR COUPLER 26 OF TABLE II

This colour coupler was prepared from 40.3 g (0.1 mole) of amine (4),0.12 mole of ethyl β,β,β-trimethoxypropionate, 2 ml of acetic acid and17.7 g (0.1 mole) of 3,4-dichlorophenylhydrazine according to theprocedure of preparation 7. The recrystallization solvent was ethyleneglycol monomethyl ether.

Yield: 15.5 g (25%). Melting point: 148° C.

PREPARATION 11: COLOUR COUPLER 32 OF TABLE II

38.9 g (0.1 mole) of amine (10) and 0.12 mole of ethylβ,β,β-trimethoxypropionate were allowed to react in acetic acid asdescribed in preparation 1.

After evaporation, 16.5 g (0.1 mole) of benzothiazolylhydrazine and 100ml of acetic acid were added to the residue. The reaction mixture washeated at 60°-70° C so that first a solution and then after about 30min. a precipitate formed. After having kept the mixture for 2 hours at60°-70° C the precipitate was filtered off by suction and treated withmethanol.

Yield: 32.5 g (50%). Melting point: 234° C.

                  Table II                                                        ______________________________________                                        Substituent in                                                                                          3-posi-                                             Colour                    tion                                                coup-                     derived M.P. Yield                                  ler   1-position          from    ° C                                                                         %                                      ______________________________________                                        1     CH.sub.2 CF.sub.3   amine   201  62.5                                                             1                                                   2     CH.sub.2C.sub.6 H.sub.5                                                                           amine   193  43                                                               2                                                   3     CH.sub.2C.sub.6 H.sub.5                                                                           amine   173  50.2                                                             1                                                   4     CH.sub.2C.sub.6 H.sub.5                                                                           amine   208  48                                                               3                                                   5     CH.sub.2 CF.sub.3   amine   188- 47.5                                                             3       190                                         6     CH.sub.2 CF.sub.3   amine   238  48.5                                                             2                                                   7     CH.sub.2 CF.sub.3   amine   185  60                                                               4                                                   8     CH.sub.2 CF.sub.3   amine   167  61.2                                                             5                                                          ##STR17##          amine 3 149  67.5                                   10    CH.sub.2 CF.sub.3   amine   139- 48.5                                                             7       141                                         11    CH.sub.2 CF.sub.3   amine   150  57.5                                                             8                                                   12    CH.sub.2 CF.sub.3   amine   110  46.5                                                             9                                                   13    CH.sub.2 C.sub.6 H.sub.5                                                                          amine    89  30                                                               9                                                   14                                                                                   ##STR18##          amine 8 200  34.5                                   15    CH.sub.2 CF.sub.3   amine   228  61                                                               10                                                  16    CH.sub.2 C.sub.6 H.sub.5                                                                          amine   235  60                                                               10                                                  17                                                                                   ##STR19##          amine 10                                                                              258  64                                     18                                                                                   ##STR20##          amine 6  74  26                                     19                                                                                   ##STR21##          amine 6 149  27.7                                   20                                                                                   ##STR22##          amine 3 163  43                                     21                                                                                   ##STR23##          amine 1 226  60                                     22                                                                                   ##STR24##          amine 1 208  60                                     23                                                                                   ##STR25##          amine 1 236  29.1                                   24                                                                                   ##STR26##          amine 2 140  38                                     25                                                                                   ##STR27##          amine 4 136  51                                     26                                                                                   ##STR28##          amine 4 148  25                                     27                                                                                   ##STR29##          amine 9 120  25                                     28                                                                                   ##STR30##          amine 9 160  12                                     29                                                                                   ##STR31##          amine 10                                                                              a- bove 240                                                                        49                                     30                                                                                   ##STR32##          amine 10                                                                              a- bove 240                                                                        44.5                                   31                                                                                   ##STR33##          amine 10                                                                              238  30                                     32                                                                                   ##STR34##          amine 10                                                                              234  30                                     ______________________________________                                    

The non-diffusible colour couplers according to the present inventioncan be incorporated into the photographic silver halide elementaccording to any suitable technique known in the art. The colourcouplers of the invention are preferably incorporated into photographichydrophilic colloid media from solutions in high boiling sparinglywater-miscible solvents such as di-n-butyl phthalate and tricresylphosphate or in low-boiling sparingly water-miscible solvents such asethyl acetate, methylene chloride, diethyl carbonate, chloroform, etc.or mixtures thereof in that they have a high solubility therein and veryfine dispersions can be obtained by means of these solvents.

For this purpose these solutions can be dispersed in extremely finedroplets, preferably in the presence of one or more wetting ordispersing agents into a hydrophilic colloid medium e.g. aqueous gelatinor into water, the low-boiling sparingly water-miscible solvent thenbeing removed by evaporation. The stable dispersions of the colourcouplers can be stored as such and then admixed whenever desired withcoating composition itself of the hydrophilic colloid layer such as asilver halide emulsion layer into which the compounds are intended to bepresent.

Of course the compounds of the invention can also be incorporated intothe hydrophilic colloid media in other ways.

More details about particularly suitable techniques that may be employedfor incorporating the colour couplers of the invention into ahydrophilic colloid layer of a photographic material there can bereferred to e.g. U.S. Pat. Nos. 2,269,158 - 2,284,887 - 2,304,939 -2,304,940 and 2,322,027, United Kingdom Patent Specification Nos.791,219 - 1,098,594 - 1,099,414 - 1,099,415 - 1,099,416 - 1,099,417 -1,218,190 - 1,272,561 and 1,297,347, French Patent Specification No.1,555,663, Belgian Patent Specification No. 722,026, German PatentSpecification No. 1,127,714 and to United Kingdom Patent SpecificationNo. 1,297,947.

The couplers according to the invention may be used in conjunction withvarious kinds of photographic emulsions. Various silver salts may beused as the sensitive salt such as silver bromide, silver iodide, silverchloride or mixed silver halides such as silver chlorobromide, silverbromoiodide and silver chlorobromoiodide. The couplers can be used inemulsions of the mixed packet type as described in U.S. Pat. No.2,698,794 or emulsions of the mixed grain type as described in U.S. Pat.No. 2,592,243. The colour couplers can be used with emulsions whereinlatent images are formed predominantly on the surface of the silverhalide crystal, or with emulsions wherein latent images are formedpredominantly inside the silver halide crystal.

The hydrophilic colloid used as the vehicle for the silver halide maybe, for example, gelatin, colloidal albumin, zein, casein, a cellulosederivative, a synthetic hydrophilic colloid such as polyvinyl alcohol,poly-N-vinyl pyrrolidone, etc. If desired, compatible mixtures of two ormore of these colloids may be employed for dispersing the silver halide.

The light-sensitive silver halide emulsions of use in the preparation ofa photographic material according to the present invention may bechemically as well as optically sensitized. They may be chemicallysensitized by effecting the ripening in the presence of small amounts ofsulphur containing compounds such as allyl thiocyanate, allyl thiourea,sodium thiosulphate, etc. The emulsions may also be sensitized by meansof reductors for instance tin compounds as described in French Pat.Specification No. 1,146,955 and in Belgian Pat. Specification No.568,687, imino-amino methane sulphinic acid compounds as described inUnited Kingdom Pat. Specification No. 789,823 and small amounts of noblemetal compounds such as gold, platinum, palladium, iridium, rutheniumand rhodium compounds. They may be optically sensitized by means ofcyanine and merocyanine dyes.

The said emulsions may also comprise compounds which sensitize theemulsions by development acceleration for example compounds of thepolyoxyalkylene type such as alkylene oxide condensation products asdescribed among others in U.S. Pat. Nos. 2,531,832 - 2,533,990 -3,210,191 and 3,158,484, in United Kingdom Pat. Specification Nos.920,637 and 991,608 and in Belgian Pat. Specification No. 648,710 andonium derivatives of amino-N-oxides as described in United Kingdom Pat.Specification No. 1,121,696.

Further, the emulsions may comprise stabilizers e.g. heterocyclicnitrogen-containing thioxo compounds such as benzothiazoline-2-thioneand 1-phenyl-2-tetrazoline-5-thione and compounds of thehydroxytriazolopyrimidine type. They can also be stabilized with mercurycompounds such as the mercury compounds described in Belgian Pat.Specification Nos. 524,121 - 677,337 and 707,386 and in U.S. Pat. No.3,179,520.

The light-sensitive emulsions may also comprise all other kinds ofingredients such as plasticizers, hardening agents, wetting agents, etc.

The non-diffusing magenta colour formers described in the presentinvention are usually incorporated into the green-sensitized silverhalide emulsion for forming one of the differently sensitized silverhalide emulsion layers of a photographic multilayer colour material.Such photographic multilayer colour material usually comprises asupport, a red-sensitized silver halide emulsion layer with a cyancolour former, a green-sensitized silver halide emulsion layer with amagenta colour former and a blue-sensitive silver halide emulsion layerwith a yellow colour former.

The emulsions can be coated on a wide variety of photographic emulsionsupports. Typical supports include cellulose ester film, polyvinylacetalfilm, polystyrene film, polyethylene terephthalate film and relatedfilms or resinous materials, as well as paper and glass. It is alsopossible to employ paper coated with α-olefin polymers e.g. paper coatedwith polyethylene, polypropylene, ethylene-butylene copolymers, etc.

For the production of photographic colour images according to thepresent invention an exposed silver halide emulsion layer is developedwith an aromatic primary amino developing substance in the presence of acolour coupler according to the present invention. All colour developingagents capable of forming azomethine dyes can be utilised as developers.Suitable developing agents are aromatic compounds such as p-phenylenediamine and derivatives for example N,N-diethyl-p-phenylene diamine,N-butyl-N-sulphobutyl-p-phenylene diamine,N-N-diethyl-N'-sulphomethyl-p-phenylene diamine,N,N-diethyl-N'-carboxymethyl-p-phenylene diamine,2-amino-5diethylaminotoluene,4-amino-N-ethyl-N(β-methanesulphonamidoethyl)-m-toluidine,N-hydroxyethyl-N-ethyl-p-phenyle diamine, etc.

The following examples illustrate the present invention.

EXAMPLE 1

An aqueous gelatin dispersion of 16 g of colour coupler 18 having thefollowing structural formula ##STR35## was admixed with 500 g of agreen-sensitized silver bromoiodide (3 mole % of iodide) emulsioncontaining 0.115 mole of silver halide.

The aqueous gelatin dispersion was prepared by dispersing with the helpof ultrasonic wave generator a solution of 6 g of colour coupler in 30ml of ethyl acetate in 100 ml of a 5% aqueous solution of gelatincontaining 1.5 g of the sodium salt of lauryl benzene sulphonate andthen removing the ethyl acetate by evaporation under reduced pressure.

After neutralization of the emulsion and addition of the commonadditives such as stabilizers, wetting agents and hardeners, theemulsion was coated on a cellulose triacetate support, dried andovercoated with a gelatin antistress layer.

The material was exposed for 1/20 sec. through a grey wedge withconstant 0.15 and developed for 8 min. at 20° C in a developing bath ofthe following composition:

    ______________________________________                                        2-amino-5-diethylaminotoluene HCl                                                                      2.5     g                                            anhydrous sodium sulphite                                                                              5       g                                            anhydrous sodium carbonate                                                                             20      g                                            potassium bromide        2       g                                            water to make            1       liter.                                       ______________________________________                                    

The silver image and residual silver halide were removed by treatment ina potassium hexacyanoferrate(III) bleach and a sodium thiosulphatefixer.

A magenta coloured wedge was obtained having absorption maximum at 556nm.

EXAMPLE 2

Another sample of the material prepared as described in example 1 wasexposed and processed in the same way with the difference that thedeveloper had the following composition:

    ______________________________________                                        2-amino-5-[N-ethyl-N(β-methylsulphonyl-                                  amino)ethyl]aminotoluene sulphate                                                                      2       g                                            anhydrous sodium sulphite                                                                              0.5     g                                            anhydrous sodium carbonate                                                                             30      g                                            water to make            1       liter                                        ______________________________________                                    

A magenta coloured wedge was obtained having absorption maximum at 556nm.

EXAMPLE 3

Examples 1 and 2 were repeated with the only difference that now colourcoupler 18 was replaced by colour coupler 19 of the following structuralformula: ##STR36##

Magenta wedge images were obtained having absorption maxima at 548 nm(developer of example 1) and 546 nm (developer of example 2).

EXAMPLE 4

Examples 1 and 2 were repeated with the only difference that colourcoupler 18 was replaced by colour coupler 20 of the following structuralformula: ##STR37##

Magenta wedge images were obtained having absorption maxima at 556 nm(developer of example 1) and 558 nm (developer of example 2).

We claim:
 1. A 3-anilino-2-pyrazolin-5-one compound having the formula:##STR38## wherein R₁ represents an alkyl group or an aryl group,Xrepresents hydrogen or a substituent that exhibits 2-equivalentcharacter selected from the group consisting of a halogen atom, analkylthio, arylthio, an alkoxy, aryloxy, acyloxy or a sulpho group; andAr represents a phenyl group carrying a phenyloxysulphonyl group.
 2. A3-anilino-2-pyrazolin-5-one compound of claim 1 wherein thephenyloxysulphonyl group is substituted with at least one of the groupsalkyl, cycloalkyl, hydroxy, halogen, alkoxy, alkylthio oralkylsulphonyl.
 3. A 3-anilino-2-pyrazolin-5-one compound having theformula: ##STR39## wherein R₁ is an aryl group, andAr is a phenyl groupcarrying a phenoxysulphonyl group.